Re: [Qemu-devel] [PATCH] configure: correctly define PTHREAD_LIB

["Daniel P. Berrange" <berrange@redhat.com>]

On Fri, Sep 29, 2017 at 04:47:01PM +0300, Alexey Perevalov wrote:
> On 09/29/2017 04:05 PM, Daniel P. Berrange wrote:
> > On Fri, Sep 29, 2017 at 03:52:34PM +0300, Alexey Perevalov wrote:
> > > On 09/29/2017 01:40 PM, Daniel P. Berrange wrote:
> > > > On Fri, Sep 29, 2017 at 01:11:14PM +0300, Alexey Perevalov wrote:
> > > > > In case of -pthread already exists in QEMU_CFLAGS,
> > > > > compilation of sample pthread program successed,
> > > > > but -pthread is not putting into PTHREAD_LIBS in this case.
> > > > > PTHREAD_LIB is using while compiling tests/migration/stress.
> > > > > 
> > > > > Signed-off-by: Alexey Perevalov <a.perevalov@samsung.com>
> > > > > ---
> > > > >    configure | 1 +
> > > > >    1 file changed, 1 insertion(+)
> > > > > 
> > > > > diff --git a/configure b/configure
> > > > > index 6587e80..a2dd044 100755
> > > > > --- a/configure
> > > > > +++ b/configure
> > > > > @@ -3359,6 +3359,7 @@ int main(void) {
> > > > >    EOF
> > > > >    if compile_prog "" "" ; then
> > > > >      pthread=yes
> > > > > +  PTHREAD_LIB="-pthread"
> > > > >    else
> > > > >      for pthread_lib in $PTHREADLIBS_LIST; do
> > > > >        if compile_prog "" "$pthread_lib" ; then
> > > > We shouldn't do this because it affects whole of QEMU. The stress program
> > > > needs -lpthread because it is linking statically, so just add it to the
> > > > Makefile rule for building stress.
> > > ok, but I didn't find any explicit usage of PTHREAD_LIB,
> > > and avoiding it in Makefile I think will make PTHREAD_LIB
> > > redundant.
> > Oh yeah, actually PTHREAD_LIB is a variable i introduced specifically
> > for the stress program, so my comment above is wrong and I think your
> > patch is ok.
> in that hardcoded form or trying to generalize it somehow?
> 
> -pthread comes to QEMU_CFLAGS from pkg-config --cflags for glib library
> so it's hard to say which one from list -pthread -lpthread -lpthreadGC2
> really lead to success build of the sample.
> So it's better to cut pthread from QEMU_CFLAGS, or you thing it's overkill?

The stress program uses pthreads so we can't just cut it. We just need to
set -pthread IMHO.

Regards,
Daniel
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